The present invention relates to a mounting for a disk file having a data storage disk, a moveable disk head and a main body supporting the disk and the head.
In a conventional disk file the data storage disk is usually mounted horizontally for rotation about a vertical axis, and is mounted on a main body or chassis. The disk head, which may be a read only head or a read and write head, is movably mounted on the main body of the disk file, for movement over the disk to desired tracks. Although in some circumstances the disk file may be permanently and rigidly fixed in a frame of other equipment, it often occurs that the disk file must be mounted so as to be easily removable from a supporting frame. For example in a tester rack it is conventional to fit each disk file into a separate carrier moulded of plastics material, and for the carrier then to be slotted into the tester rack. In other applications, a removable disk file may be removably mounted in a computer.
In some arrangements the disk file may be mounted vertically for rotation about a horizontal axis. In general in this specification, where an example of a disk file is described with the disk in a horizontal plane, it is to be appreciated that the description applies equally well to a disk file positioned in a vertical plane for rotation about a horizontal axis, or indeed in other configurations where appropriate.
A problem which arises in the operation of disk files occurs at the end of the seek movement of the disk head to a desired track. The access acceleration and deceleration of the actuator, containing the read/write heads, particularly on high performance disk files, results in an equivalent reaction to the main body of the disk file. This reaction can cause the file to oscillate in its mounting, and hence the reaction provides an input to the file. The result is unwanted misregistration of the head to the track. In recent years the actuators on disk files have generally changed from linear to rotary operation, the read/write heads being moved in an arc across the disk, about a vertical axis (for a horizontal disk) positioned on the main body of the disk file, outside the perimeter of the disk. The vibrations arising from acceleration and deceleration of such a rotary actuator produce rotary oscillation of the main body of the disk file in a horizontal plane.
One way of reducing or avoiding the effects of such vibration is to mount the main body of the file very firmly in a grounded frame, secured against rotary vibration, and another method is to mount the main body of the disk file on a floating mounting, or one which allows movement only at such a low frequency that the actuator servo can follow the vibration with only a small error. If the file is not mounted at one of these extremes (rigidly mounted or on a floating mounting) the mount vibration will appear on the head/track error signal after the file has met its on-track criteria. The resulting misregistration is detected, causing what is generally known as a Write Fault Error, preventing the file from writing, with a consequent reduction in file performance.
In situations where easy removability of the disk file is required, mounting at either of the extreme situations mentioned above is difficult. In a file tester rack for example, removal should be as simple as possible. The tester should also be space efficient, which rules out a low frequency mount option since this would require too large a space. Finally, the tester frame should be capable of manufacture at a reasonably low cost.
It has been known in the past to secure a disk file by a cam having a wedge shaped profile, but this has been done to secure the disk file during transit in a non-operating position. In U.S. Pat. No. 4,896,777 (Lewis) there is disclosed a mounting system for mounting a disk drive mechanism in a computer circuit board card cage. The mounting includes a plurality of shock mounts provided two on each side of the disk drive mechanism for mounting the disk drive during normal operational use. In addition there are provided four locking pins for holding the disk drive in an inoperative position when they engage in appropriate openings in the sides of the disk drive mechanism. A control mechanism for controlling the locking pins comprises displaceable cams which can be moved relative to the mounting to push the locking pins into engagement with the disk drive mechanism. The displaceable cams have a wedge shaped profile. The use of the cams is to move the locking pins into position for holding the disk drive in an inoperative position, and the locking pins are released during normal operation of the disk drive.